Ten US Navy sailors are missing after a US Navy guided-missile destroyer collided with a merchant ship east of Singapore early Monday, the Navy said in a statement.

The Navy’s 7th Fleet said the USS John S. McCain collided with the merchant vessel Alnic MC while the destroyer was making its way to a port visit in Singapore. The collision was reported at 5:24 am local time, according to the Navy statement.

A Navy official told CNN the McCain was fighting flooding in several places and that it had limited propulsion and electrical power.

In addition to the 10 missing sailors, the Navy said five were injured in the collision.

Search and rescue efforts are under way, the Navy statement said, with helicopters and Marine Corps Osprey aircraft from the amphibious assault ship USS America responding.

Singaporean ships and helicopters were also responding, the Navy said.

Initial reports indicate the US ship sustained damage to its aft port (rear left) side, the Navy statement said. It said the McCain was steaming under its own power to port.

All four of the US warships are equipped with the Aegis missile defense system, which has been touted as a possible defense against any North Korean missile launch that might endanger US forces and US allies in Asia.

The USS John S. McCain is named for the father and grandfather of US Sen. John McCain. Both of McCain’s relatives were US Navy admirals. The senator was a captain in the US Navy.